Magnesium hydroxide, the active ingredient in milk of magnesia, neutralizes stomach acid, primarily HCl, according to the reaction in the following: Mg (OH) 2 (aq) + 2HCl (aq) →2H2O (l) + MgCl2 (aq) What mass of HCl, in grams, is neutralized by a dose of milk of magnesia containing 3.26 g of Mg (OH) 2?

4.076g of HCl is neutralized by a dose of milke of magnesia containing 3.26g of Mg (OH) 2

Explanation:

Step 1: The balanced equation

Mg (OH) ₂ (aq) + 2 HCl (aq) ⇔ 2 H₂O (l) + MgCl₂ (aq)

This means that for 1 mole of Magnesium hydroxide consumed, there i s consumed 2 moles of HCl and there is produced 1 mole of MgCl2 (and 2 moles of H2O)

Step 2: Calculating moles of Mg (OH) 2

moles of Mg (OH) 2 = mass of Mg (OH) 2 / Molar mass of Mg (OH) 2

moles Mg (OH) 2 = 3.26g / 58.32g/mole = 0.0559 mole Mg (OH) 2

Step 3: Calculating moles of HCl

Since there is for 1 mole Mg (OH) 2 consumed, there is consumed 2 moles of HCl

There is for each 0.0559 moles of Mg (OH) 2, 2*0.0559 = 0.1118 moles of HCl consumed.

Step 4: Calculating mass of HCl

mass of HCl = moles of HCl x Molar mass of HCl

mass of HCl = 0.1118 moles * 36.46 g/mole

mass of HCl = 4.076 g

4.076g of HCl is neutralized by a dose of milke of magnesia containing 3.26g of Mg (OH) 2